City of Sydney

Background and Context

The City of Sydney (COS) has set a target of reducing greenhouse gas emissions across the entire local government area by 70% below 2006 levels by 2030. The feasibility study for this project was completed by Kinesis and Cogent energy. Cogent Energy provided: detailed knowledge of cogeneration and tri-generation systems to assist with their implementation throughout the Sydney CBD; the knowledge of accurate building loads to model the approximate demand of the Sydney CBD; and their knowledge and experience with implementing district cooling and heating systems within Australian business districts.

Their role in this study, later led to their appointment as the head engineers and project managers for the COS project.

Solution Overview

The study looked at the viability and potential design of centralised energy generation facilities within the Sydney CBD, including thermal energy distribution.

The study found gas reciprocating engines to be the most viable form of energy generation, given their higher electrical efficiency of 42% when compared with turbines (36%).

The installed capacity of 360MWe allowed the optimal plant utilization of 60%

Given the restricted operating temperature range of the city’s space cooling requirements, the study found distribution of low temperature hot water through an insulated, underground pipe network to be the most efficient form of thermal distribution. Building owners would then utilise this heat through absorption chillers to provide the buildings cooling requirements.

The best balance of high greenhouse gas emission savings to economic return was found when operating the tri-generation plants over the peak period of 7am to 10pm, when grid electricity prices are at their highest.

The study proposed the inclusion of thermal storage in the order of 700MWh, in the form of multiple storage devices totaling approximately 40ML. This stored heat would be used to meet overnight and shoulder thermal demands.

The proposed capacities plant to be installed across 15 sites across 4 main precincts: CBD North, CBD South, Green Square and Pyromont.

The study looked at the viability and potential design of centralised energy generation facilities within the Sydney CBD, including thermal energy distribution.